travel among galaxies and accelerate the evolution of intelligent life changed into the dust found by the ancient humans (the latter created the Flood) These orbital bridges, or 'star roads' were used in the final stages of the Forerunner-Flood war. They seemingly caused local space-time to warp and mutate when using their version of slipspace travel. Neural physics was a Precursor concept. The Precursors felt that the Mantle extended to the entire universe, including energy and matter. The principles of neural physics also postulated that the entire universe was living, but in a way that was beyond the comprehension of biological organisms.[1] Precursor technology was based upon the principles of neural physics. While this normally made most Precursor artifacts effectively indestructible Unbending filaments were a type of Precursor construction. It was noted that they could link entire worlds and systems. Like most Precursor technology, they were also virtually indestructible Tier 0: Transsentient Some Precursor artifacts were known to precede the Forerunners by hundreds of millions of years, and, being impervious to conventional forms of damage, were durable enough to survive being cycled inside planets' crusts by plate tectonics These artifacts—mainly star roads—were what eventually turned the war in the Flood's favor as they were capable of effortlessly either outright physically tearing apart Forerunner fleets or remotely deactivating their weapons, AIs and shields, rendering them helpless against the Flood After reaching the Key Mind stage, Flood compound minds gained the ability to tap into neural physics and along with it the Precursors' reality-mutation capabilities.[31] When moving across the galaxy, Flood-controlled Precursor constructs would convert space-time itself to be unsuitable for Forerunner slipspace drives Precursors possessed unknown means of correcting causality The widespread use of neural physics transit affected the galactic-scale magnetic fields that marked the borders of the ecumene's themas vast reserve containing the totality of the Precursors' accumulated knowledge and experience - amounting to a hundred billion years, with most of the information gathered originating from the beginning of the universe, or earlier. This reserve of knowledge was contained in Precursor constructs in the Milky Way galaxy and projected a massive field through which the records could be accessed anywhere regardless of locality. The Domain itself was also a conscious entity, although this only became apparent near the end of the Forerunner-Flood war